Priority Handling for Prose Communications

ABSTRACT

Systems, methods, and instrumentalities are disclosed for priority handling for ProSe Communications. A relay wireless transmit/receive unit (WTRU) may act as a relay between the network and the remote WTRU. The relay WTRU may receive a temporary mobile group identity (TMGI) request message from a remote WTRU. The TMGI request message may include a TMGI, a ProSe per packet priority level associated with the TMGI, etc. The relay WTRU may receive an evolved multimedia broadcast multicast service (eMBMS) data packet from a network. The eMBMS may be associated with the TMGI. The relay WTRU may apply the received ProSe per packet priority level associated with the TMGI to the received eMBMS data packet. The relay WTRU may relay the eMBMS data packet to the remote WTRU based on the ProSe per packet priority level. The relay WTRU may forward the eMBMS data packet to the remote WTRU via a PC5 interface.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Nos. 62/183,629 filed on Jun. 23, 2015, 62/203,681 filed onAug. 11, 2015, and 62/250,793 filed on Nov. 4, 2015, the contents ofwhich are hereby incorporated by reference herein.

BACKGROUND

A relay wireless transmit/receive unit (WTRU) may provide connectivityto a remote WTRU that may be out of coverage of a network. The relayWTRU may communicate with the remote WTRU via a PC5 interface. Proximityservices (ProSe) may enable a direct communication between the relayWTRU and the remote WTRU using, for example, LTE radio interfaces.Unlike communications over a Uu interface between a relay WTRU and aneNodeB, ProSe communications over the PC5 interface between a relay WTRUand a remote WTRU may not support quality of service (QoS). PC5interface may support ProSe per packet priority. A relay WTRU may needmechanisms to determine a ProSe per packet priority value.

SUMMARY

Systems, methods, and instrumentalities are disclosed for priorityhandling for ProSe communications. A relay wireless transmit/receiveunit (WTRU) may act as a relay between the network and the remote WTRU.The relay may receive a temporary mobile group identity (TMGI) requestmessage from a remote WTRU. The TMGI request message may include a TMGI,a ProSe per packet priority level associated with the TMGI, etc. TheTMGI request message may be a PC5-S message. The relay WTRU may receive,from a network, an evolved multimedia broadcast multicast service(eMBMS) data packet associated with the TMGI. The relay WTRU may detectthe TMGI, the relay is configured to monitor. The WTRU may apply thereceived ProSe per packet priority level associated with the TMGI to thereceived eMBMS data packet. The relay WTRU may relay the eMBMS datapacket to the remote WTRU based on the ProSe per packet priority level.The relay WTRU may send the eMBMS packet over the PC5 interface. Therelay WTRU may act as a relay between the network and the remote WTRU.

A remote WTRU may receive a service announcement from an applicationserver (AS). The service announcement may include a TMGI and a prioritylevel associated with the TMGI. The remote WTRU may determine a ProSeper packet priority level associated with the TMGI. For example, theremote WTRU may derive the ProSe per packet priority level from thereceived priority level associated with the TMGI. The remote WTRU maysend a TMGI message to a relay WTRU. The TMGI message may be sent usinga PC5-S transmission. The PC5-S transmission may be sent using apre-configured ProSe per packet priority level. The PC5-S transmissionmay be sent using a priority level is received from a network node(e.g., a mobile management entity (MME) or a ProSe function). The TMGImessage may include the TMGI and the determined ProSe per packetpriority level associated with the TMGI. The ProSe per packet prioritylevel associated with the TMGI may be indicated using one of eightpossible values. The remote WTRU may receive, from the relay WTRU, anevolved multimedia broadcast multicast service (eMBMS) data packetassociated with the TMGI.

The remote WTRU may include a lower layer (e.g., a PC5 access stratumlayer) and an upper layer (e.g., a PC5 ProSe layer). The lower layer ofthe remote WTRU may receive one or more ProSe per packet priorities fromthe upper layer. The lower layer may receive one or more protocol dataunits (PDUs) from the upper layer. The lower layer may prioritize thePDUs received from the upper layer based on the ProSe per packetpriorities received from the upper layer. The ProSe per packet priorityvalues may be independent of destination addresses. The PDUs withdifferent priorities may be served in order. A ProSe per packet priorityassociated with a PDU with lower number may have higher priority than aProSe per packet priority associated with a PDU with higher number.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a system diagram of an example communications system in whichone or more disclosed embodiments may be implemented.

FIG. 1B is a system diagram of an example wireless transmit/receive unit(WTRU) that may be used within the communications system illustrated inFIG. 1A.

FIG. 1C is a system diagram of an example radio access network and anexample core network that may be used within the communications systemillustrated in FIG. 1A.

FIG. 1D is a system diagram of another example radio access network andanother example core network that may be used within the communicationssystem illustrated in FIG. 1A.

FIG. 1E is a system diagram of another example radio access network andanother example core network that may be used within the communicationssystem illustrated in FIG. 1A.

FIG. 2 illustrates an example of a WTRU-to-Network relay architecture.

FIG. 3 illustrates an example of a PC5-S protocol stack.

FIG. 4 illustrates an example of a WTRU ProSe layer.

FIG. 5 illustrates an example of a WTRU ProSe layer when a Transmission(Tx) with a priority level (e.g., a new priority level) is requested,e.g., with or without a specific destination address.

FIG. 6 illustrates an example of a WTRU or a WTRU ProSe layer sending aPC-5 message with priority information.

FIG. 7 illustrates an example of a WTRU or a WTRU ProSe layer receivingand processing a PC-5 message with priority information.

FIG. 8 illustrates an example of WTRU establishing a ProSe session withpriority levels and/or ProSe context.

FIG. 9 illustrates an example of a WTRU (e.g., a relay WTRU) or ProSelayer sending a PC5-S message with modified priority information.

FIG. 10 illustrates an example of modifying a ProSe context or priorityfor a ProSe link or communication between two WTRUs, e.g., for one ormore logical channel IDs.

FIG. 11 illustrates an example of a relay WTRU or a ProSe layerreceiving and/or processing a PC5-S message with priority informationand determining appropriate evolved packet system (EPS) bearer mapping.

FIG. 12 illustrates an example of determining priority information ofMBMS data.

FIG. 13 illustrates an example of a relay WTRU receiving MBMS priorityinformation or ProSe per packet priority information from a remote WTRU.

FIG. 14 illustrates an example of handling priority for a PC5 signaling(PC5-S) message.

FIG. 15 illustrates an example of determining a priority level fortransmitting a PC5-S message.

FIG. 16 illustrates an example of updating a PPP value of PC5-S messagesbased on a highest PPP (e.g., a new highest PPP) of a PC5-Utransmission.

DETAILED DESCRIPTION

A detailed description of illustrative embodiments will now be describedwith reference to the various Figures. Although this descriptionprovides a detailed example of possible implementations, it should benoted that the details are intended to be exemplary and in no way limitthe scope of the application.

FIG. 1A is a diagram of an example communications system 100 in whichone or more disclosed embodiments may be implemented. The communicationssystem 100 may be a multiple access system that provides content, suchas voice, data, video, messaging, broadcast, etc., to multiple wirelessusers. The communications system 100 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications system 100may employ one or more channel access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs), e.g., WTRUs, 102 a, 102 b, 102 c, and/or102 d (which generally or collectively may be referred to as WTRU 102),a radio access network (RAN) 103/104/105, a core network 106/107/109, apublic switched telephone network (PSTN) 108, the Internet 110, andother networks 112, though it will be appreciated that the disclosedembodiments contemplate any number of WTRUs, base stations, networks,and/or network elements. Each of the WTRUs 102 a, 102 b, 102 c, 102 dmay be any type of device configured to operate and/or communicate in awireless environment. By way of example, the WTRUs 102 a, 102 b, 102 c,102 d may be configured to transmit and/or receive wireless signals andmay include user equipment (UE), a mobile station, a fixed or mobilesubscriber unit, a pager, a cellular telephone, a personal digitalassistant (PDA), a smartphone, a laptop, a netbook, a personal computer,a wireless sensor, consumer electronics, and the like.

The communications system 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the core network 106/107/109, theInternet 110, and/or the networks 112. By way of example, the basestations 114 a, 114 b may be a base transceiver station (BTS), a Node-B,an eNode B, a Home Node B, a Home eNode B, a site controller, an accesspoint (AP), a wireless router, and the like. While the base stations 114a, 114 b are each depicted as a single element, it will be appreciatedthat the base stations 114 a, 114 b may include any number ofinterconnected base stations and/or network elements.

The base station 114 a may be part of the RAN 103/104/105, which mayalso include other base stations and/or network elements (not shown),such as a base station controller (BSC), a radio network controller(RNC), relay nodes, etc. The base station 114 a and/or the base station114 b may be configured to transmit and/or receive wireless signalswithin a particular geographic region, which may be referred to as acell (not shown). The cell may further be divided into cell sectors. Forexample, the cell associated with the base station 114 a may be dividedinto three sectors. Thus, in some embodiments, the base station 114 amay include three transceivers, e.g., one for each sector of the cell.In another embodiment, the base station 114 a may employ multiple-inputmultiple output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 115/116/117,which may be any suitable wireless communication link (e.g., radiofrequency (RF), microwave, infrared (IR), ultraviolet (UV), visiblelight, etc.). The air interface 115/116/117 may be established using anysuitable radio access technology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 103/104/105 and the WTRUs 102a, 102 b, 102 c may implement a radio technology such as UniversalMobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA),which may establish the air interface 115/116/117 using wideband CDMA(WCDMA). WCDMA may include communication protocols such as High-SpeedPacket Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may includeHigh-Speed Downlink Packet Access (HSDPA) and/or High-Speed UplinkPacket Access (HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface115/116/117 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.16 (e.g.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,CDMA2000 1×, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE), GSM EDGE (GERAN), and the like.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, and the like. In someembodiments, the base station 114 b and the WTRUs 102 c, 102 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 114 band the WTRUs 102 c, 102 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 114 b and the WTRUs 102 c, 102 dmay utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A,the base station 114 b may have a direct connection to the Internet 110.Thus, the base station 114 b may not be required to access the Internet110 via the core network 106/107/109.

The RAN 103/104/105 may be in communication with the core network106/107/109, which may be any type of network configured to providevoice, data, applications, and/or voice over internet protocol (VoIP)services to one or more of the WTRUs 102 a, 102 b, 102 c, 102 d. Forexample, the core network 106/107/109 may provide call control, billingservices, mobile location-based services, pre-paid calling, Internetconnectivity, video distribution, etc., and/or perform high-levelsecurity functions, such as user authentication. Although not shown inFIG. 1A, it will be appreciated that the RAN 103/104/105 and/or the corenetwork 106/107/109 may be in direct or indirect communication withother RANs that employ the same RAT as the RAN 103/104/105 or adifferent RAT. For example, in addition to being connected to the RAN103/104/105, which may be utilizing an E-UTRA radio technology, the corenetwork 106/107/109 may also be in communication with another RAN (notshown) employing a GSM radio technology.

The core network 106/107/109 may also serve as a gateway for the WTRUs102 a, 102 b, 102 c, 102 d to access the PSTN 108, the Internet 110,and/or other networks 112. The PSTN 108 may include circuit-switchedtelephone networks that provide plain old telephone service (POTS). TheInternet 110 may include a global system of interconnected computernetworks and devices that use common communication protocols, such asthe transmission control protocol (TCP), user datagram protocol (UDP)and the internet protocol (IP) in the TCP/IP internet protocol suite.The networks 112 may include wired or wireless communications networksowned and/or operated by other service providers. For example, thenetworks 112 may include another core network connected to one or moreRANs, which may employ the same RAT as the RAN 103/104/105 or adifferent RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, e.g., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 1A may be configured tocommunicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram of an example WTRU 102. As shown in FIG. 1B,the WTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element 122, a speaker/microphone 124, a keypad 126, adisplay/touchpad 128, non-removable memory 130, removable memory 132, apower source 134, a global positioning system (GPS) chipset 136, andother peripherals 138. It will be appreciated that the WTRU 102 mayinclude any sub-combination of the foregoing elements while remainingconsistent with an embodiment. Also, embodiments contemplate that thebase stations 114 a and 114 b, and/or the nodes that base stations 114 aand 114 b may represent, such as but not limited to transceiver station(BTS), a Node-B, a site controller, an access point (AP), a home node-B,an evolved home node-B (eNodeB), a home evolved node-B (HeNB orHeNodeB), a home evolved node-B gateway, and proxy nodes, among others,may include some or all of the elements depicted in FIG. 1B anddescribed herein.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 115/116/117. For example, in some embodiments,the transmit/receive element 122 may be an antenna configured totransmit and/or receive RF signals. In another embodiment, thetransmit/receive element 122 may be an emitter/detector configured totransmit and/or receive IR, UV, or visible light signals, for example.In yet another embodiment, the transmit/receive element 122 may beconfigured to transmit and receive both RF and light signals. It will beappreciated that the transmit/receive element 122 may be configured totransmit and/or receive any combination of wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in some embodiments, the WTRU 102 mayinclude two or more transmit/receive elements 122 (e.g., multipleantennas) for transmitting and receiving wireless signals over the airinterface 115/116/117.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 115/116/117from a base station (e.g., base stations 114 a, 114 b) and/or determineits location based on the timing of the signals being received from twoor more nearby base stations. It will be appreciated that the WTRU 102may acquire location information by way of any suitablelocation-determination implementation while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 1C is a system diagram of the RAN 103 and the core network 106according to an embodiment. As noted above, the RAN 103 may employ aUTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102 cover the air interface 115. The RAN 103 may also be in communicationwith the core network 106. As shown in FIG. 1C, the RAN 103 may includeNode-Bs 140 a, 140 b, 140 c, which may each include one or moretransceivers for communicating with the WTRUs 102 a, 102 b, 102 c overthe air interface 115. The Node-Bs 140 a, 140 b, 140 c may each beassociated with a particular cell (not shown) within the RAN 103. TheRAN 103 may also include RNCs 142 a, 142 b. It will be appreciated thatthe RAN 103 may include any number of Node-Bs and RNCs while remainingconsistent with an embodiment.

As shown in FIG. 1C, the Node-Bs 140 a, 140 b may be in communicationwith the RNC 142 a. Additionally, the Node-B 140 c may be incommunication with the RNC 142 b. The Node-Bs 140 a, 140 b, 140 c maycommunicate with the respective RNCs 142 a, 142 b via an Iub interface.The RNCs 142 a, 142 b may be in communication with one another via anIur interface. Each of the RNCs 142 a, 142 b may be configured tocontrol the respective Node-Bs 140 a, 140 b, 140 c to which it isconnected. In addition, each of the RNCs 142 a, 142 b may be configuredto carry out or support other functionality, such as outer loop powercontrol, load control, admission control, packet scheduling, handovercontrol, macrodiversity, security functions, data encryption, and thelike.

The core network 106 shown in FIG. 1C may include a media gateway (MGW)144, a mobile switching center (MSC) 146, a serving GPRS support node(SGSN) 148, and/or a gateway GPRS support node (GGSN) 150. While each ofthe foregoing elements are depicted as part of the core network 106, itwill be appreciated that any one of these elements may be owned and/oroperated by an entity other than the core network operator.

The RNC 142 a in the RAN 103 may be connected to the MSC 146 in the corenetwork 106 via an IuCS interface. The MSC 146 may be connected to theMGW 144. The MSC 146 and the MGW 144 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional land-line communications devices.

The RNC 142 a in the RAN 103 may also be connected to the SGSN 148 inthe core network 106 via an IuPS interface. The SGSN 148 may beconnected to the GGSN 150. The SGSN 148 and the GGSN 150 may provide theWTRUs 102 a, 102 b, 102 c with access to packet-switched networks, suchas the Internet 110, to facilitate communications between and the WTRUs102 a, 102 b, 102 c and IP-enabled devices.

As noted above, the core network 106 may also be connected to thenetworks 112, which may include other wired or wireless networks thatare owned and/or operated by other service providers.

FIG. 1D is a system diagram of the RAN 104 and the core network 107according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116. The RAN 104 may also be in communicationwith the core network 107.

The RAN 104 may include eNode-Bs 160 a, 160 b, 160 c, though it will beappreciated that the RAN 104 may include any number of eNode-Bs whileremaining consistent with an embodiment. The eNode-Bs 160 a, 160 b, 160c may each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In someembodiments, the eNode-Bs 160 a, 160 b, 160 c may implement MIMOtechnology. Thus, the eNode-B 160 a, for example, may use multipleantennas to transmit wireless signals to, and receive wireless signalsfrom, the WTRU 102 a.

Each of the eNode-Bs 160 a, 160 b, 160 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the uplink (UL) and/or downlink (DL), and the like. As shown in FIG.1D, the eNode-Bs 160 a, 160 b, 160 c may communicate with one anotherover an X2 interface.

The core network 107 shown in FIG. 1D may include a mobility managementgateway (MME) 162, a serving gateway 164, and a packet data network(PDN) gateway 166. While each of the foregoing elements are depicted aspart of the core network 107, it will be appreciated that any one ofthese elements may be owned and/or operated by an entity other than thecore network operator.

The MME 162 may be connected to each of the eNode-Bs 160 a, 160 b, 160 cin the RAN 104 via an S1 interface and may serve as a control node. Forexample, the MME 162 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and the like. The MME 162 may also provide a control planefunction for switching between the RAN 104 and other RANs (not shown)that employ other radio technologies, such as GSM or WCDMA.

The serving gateway 164 may be connected to each of the eNode-Bs 160 a,160 b, 160 c in the RAN 104 via the S1 interface. The serving gateway164 may generally route and forward user data packets to/from the WTRUs102 a, 102 b, 102 c. The serving gateway 164 may also perform otherfunctions, such as anchoring user planes during inter-eNode B handovers,triggering paging when downlink data is available for the WTRUs 102 a,102 b, 102 c, managing and storing contexts of the WTRUs 102 a, 102 b,102 c, and the like.

The serving gateway 164 may also be connected to the PDN gateway 166,which may provide the WTRUs 102 a, 102 b, 102 c with access topacket-switched networks, such as the Internet 110, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and IP-enableddevices.

The core network 107 may facilitate communications with other networks.For example, the core network 107 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional land-line communications devices. For example, the corenetwork 107 may include, or may communicate with, an IP gateway (e.g.,an IP multimedia subsystem (IMS) server) that serves as an interfacebetween the core network 107 and the PSTN 108. In addition, the corenetwork 107 may provide the WTRUs 102 a, 102 b, 102 c with access to thenetworks 112, which may include other wired or wireless networks thatare owned and/or operated by other service providers.

FIG. 1E is a system diagram of the RAN 105 and the core network 109according to an embodiment. The RAN 105 may be an access service network(ASN) that employs IEEE 802.16 radio technology to communicate with theWTRUs 102 a, 102 b, 102 c over the air interface 117. As will be furtherdiscussed below, the communication links between the differentfunctional entities of the WTRUs 102 a, 102 b, 102 c, the RAN 105, andthe core network 109 may be defined as reference points.

As shown in FIG. 1E, the RAN 105 may include base stations 180 a, 180 b,180 c, and an ASN gateway 182, though it will be appreciated that theRAN 105 may include any number of base stations and ASN gateways whileremaining consistent with an embodiment. The base stations 180 a, 180 b,180 c may each be associated with a particular cell (not shown) in theRAN 105 and may each include one or more transceivers for communicatingwith the WTRUs 102 a, 102 b, 102 c over the air interface 117. In someembodiments, the base stations 180 a, 180 b, 180 c may implement MIMOtechnology. Thus, the base station 180 a, for example, may use multipleantennas to transmit wireless signals to, and receive wireless signalsfrom, the WTRU 102 a. The base stations 180 a, 180 b, 180 c may alsoprovide mobility management functions, such as handoff triggering,tunnel establishment, radio resource management, traffic classification,quality of service (QoS) policy enforcement, and the like. The ASNgateway 182 may serve as a traffic aggregation point and may beresponsible for paging, caching of subscriber profiles, routing to thecore network 109, and the like.

The air interface 117 between the WTRUs 102 a, 102 b, 102 c and the RAN105 may be defined as an R1 reference point that implements the IEEE802.16 specification. In addition, each of the WTRUs 102 a, 102 b, 102 cmay establish a logical interface (not shown) with the core network 109.The logical interface between the WTRUs 102 a, 102 b, 102 c and the corenetwork 109 may be defined as an R2 reference point, which may be usedfor authentication, authorization, IP host configuration management,and/or mobility management.

The communication link between each of the base stations 180 a, 180 b,180 c may be defined as an R8 reference point that includes protocolsfor facilitating WTRU handovers and the transfer of data between basestations. The communication link between the base stations 180 a, 180 b,180 c and the ASN gateway 182 may be defined as an R6 reference point.The R6 reference point may include protocols for facilitating mobilitymanagement based on mobility events associated with each of the WTRUs102 a, 102 b, 102 c.

As shown in FIG. 1E, the RAN 105 may be connected to the core network109. The communication link between the RAN 105 and the core network 109may defined as an R3 reference point that includes protocols forfacilitating data transfer and mobility management capabilities, forexample. The core network 109 may include a mobile IP home agent(MIP-HA) 184, an authentication, authorization, accounting (AAA) server186, and a gateway 188. While each of the foregoing elements aredepicted as part of the core network 109, it will be appreciated thatany one of these elements may be owned and/or operated by an entityother than the core network operator.

The MIP-HA may be responsible for IP address management, and may enablethe WTRUs 102 a, 102 b, 102 c to roam between different ASNs and/ordifferent core networks. The MIP-HA 184 may provide the WTRUs 102 a, 102b, 102 c with access to packet-switched networks, such as the Internet110, to facilitate communications between the WTRUs 102 a, 102 b, 102 cand IP-enabled devices. The AAA server 186 may be responsible for userauthentication and for supporting user services. The gateway 188 mayfacilitate interworking with other networks. For example, the gateway188 may provide the WTRUs 102 a, 102 b, 102 c with access tocircuit-switched networks, such as the PSTN 108, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and traditionalland-line communications devices. In addition, the gateway 188 mayprovide the WTRUs 102 a, 102 b, 102 c with access to the networks 112,which may include other wired or wireless networks that are owned and/oroperated by other service providers.

Although not shown in FIG. 1E, it will be appreciated that the RAN 105may be connected to other ASNs and the core network 109 may be connectedto other core networks. The communication link between the RAN 105 theother ASNs may be defined as an R4 reference point, which may includeprotocols for coordinating the mobility of the WTRUs 102 a, 102 b, 102 cbetween the RAN 105 and the other ASNs. The communication link betweenthe core network 109 and the other core networks may be defined as an R5reference, which may include protocols for facilitating interworkingbetween home core networks and visited core networks.

A ProSe WTRU-to-Network relay service may be provided. A WTRU (e.g., aProSe WTRU-to-Network relay) may act as a relay to a remote WTRU. Therelay WTRU may provide IP connectivity service to one or more remoteWTRUs that may be out of network coverage. A ProSe WTRU-to-Network relaymay be referred to as a relay WTRU. A relay WTRU may provide unicastand/or multicast services to one or more remote WTRUs. FIG. 2illustrates an exemplary ProSe WTRU-to-Network relay architecture. Asillustrated in FIG. 2 , a relay WTRU may act like a layer 3 (L3) router.The relay WTRU may provide a unicast service and/or a broadcast serviceto the remote WTRU. The relay WTRU may perform L3 forwarding for one ormore of uplink (UL) traffic or downlink (DL) traffic.

A relay WTRU may relay MBMS traffic that it may detect from a network. Aremote WTRU may indicate to a relay WTRU the MBMS data the remote WTRUmay be interested in. The remote WTRU may provide to the relay WTRU aTMGI associated with the interested MBMS data. The relay WTRU maybroadcast MBMS data (e.g., related to the indicated TMGI). The MBMS datamay be broadcasted over a PC5 communication plane.

Proximity services (ProSe) may enable direct communication betweendevices using an LTE radio interface (e.g., an Evolved UMTS TerrestrialRadio Access Network (E-UTRAN) interface). Communication over an EvolvedPacket Core (EPC) may support Quality of Service (QoS). ProSe may notsupport quality of service (QoS). ProSe may support priority handling ofIP packets sent over a direct link. An IP packet may be associated witha priority level. A priority level may indicate how the access stratumin a device may treat a packet (e.g., based on a priority value) duringtransmission. ProSe priority may be referred to as ProSe per packetpriority (PPP or PPPP) or PC5 ProSe priority or PC5 priority.

A priority of a ProSe communication transmission may be selected, forexample, by an application layer. The ProSe communication transmissionmay be selected based on one or more criteria. Interaction between anapplication layer and one or more ProSe communication lower layers maybe neutral to how a ProSe WTRU may access a medium, for example, using ascheduled mode or an autonomous transmission mode.

Upper layers in a remote WTRU may provide a ProSe per packet priorityfrom a range of possible values to one or more lower layers. Forexample, ProSe per packet priority value may be provided when requestinga transmission, such as one-to-one or one-to-many communication. ProSeper packet priority of a transmission may be independent of adestination address.

An access stratum layer may use a ProSe per packet priority associatedwith a protocol data unit received from upper layers, for example, toprioritize multiple intra-WTRU transmissions and inter-WTRUtransmissions. An intra-WTRU transmission may be protocol data unitsassociated with different priorities awaiting transmission inside thesame WTRU.

Priority queues (e.g., intra-WTRU and inter-WTRU priority queues) may beserved in a priority order. For example, a scheduler in WTRU or eNB mayserve packets associated with ProSe per packet priority N before servingpackets associated with priority N+1. A lower number may be designate ahigher priority. A medium may be accessed in scheduled or autonomoustransmission modes, for example, while respecting a ProSe per packetpriority value selected by applications. One or more priority levels(e.g., eight priority levels) may be supported for a ProSe per packetpriority, for example, to support a wide range of applications.

E-UTRAN may be able to validate and/or limit, per WTRU, a maximum ProSeper packet priority that may be granted to a WTRU. A framework fordefining mapping of application traffic types to one or more values ofProSe per packet priority may be defined.

A signaling plane may be provided in ProSe communication. Signaling(e.g., ProSe related signaling) may be transmitted, for example, tonegotiate one or more parameters (e.g., IP address, port number,parameters for MBMS data) to be used for transmission of IP data or userplane data. The ProSe related signaling may be transmitted before aProSe communication session is initiated between devices. Transport of aProSe Signaling Protocol may be referred to as PC5-S. PC5-S transmissionmay be carried over IP or PDCP.

FIG. 3 illustrates an example of a PC5 signaling (PC5-S) protocol stack.A packet data convergence protocol (PDCP) header (e.g., a service dataunit (SDU) type field in a PDCP header) may be used, for example, todiscriminate between IP packets, allocation and retention priority(ARP), and PC5-S signaling protocol. Packets that carry signaling (e.g.,using PC5-S protocol) may be handled in a manner similar to the handlingof user plane packets. Packets that carry signaling may be subject tothe same priority treatment. A PPP may be associated with each of thePC5-S protocol data units (PDUs).

A remote WTRU may be out of coverage of a network. A remote WTRU may usethe connectivity of a WTRU-to-Network relay. The WTRU-to-Network relaymay act as a Layer 3 router, e.g., as shown in FIG. 2 . There may be oneor more problems handling priority for relayed traffic, e.g., withrespect to handling priority at a WTRU-to-Network relay for unicasttraffic or MBMS data, handling priority for PC5-S traffic.

A remote WTRU may receive a priority associated with a packet that itmay transmit over a PC5-U interface. The remote WTRU may receive thepriority (e.g., PPP) from an application server. The priority may beprovided by the application layer of the WTRU to one or more of itslower layers. Such application layer may be absent in a relay WTRU. Therelay WTRU may lack an ability to handle the priority of an IP packet itmay receive from the network in a downlink (DL) direction. The IP packetmay be destined to one or more remote WTRUs, e.g., over the PC5-Uinterface. A WTRU behavior may indicate how a relay WTRU handles theconcept of PPP, such as treatment of packets to be transmitted on thePC5-U towards one or more remote WTRUs.

A relay WTRU may receive data from a remote WTRU. The relay WTRU may nothave information about the priority, the remote WTRU may have used whilesending the packet. One way of obtaining such information may be bypre-configuring the relay WTRU and the remote WTRU. Such information mayenable the relay WTRU to forward received packets from a remote WTRU(e.g., over PC5-U) on an appropriate evolved packet system (EPS) bearerthat is associated with a quality of service (QoS).

A relay WTRU may support relaying of eMBMS data. A relay WTRU mayreceive eMBMS data that may be of interest to remote WTRUs, e.g., on abroadcast channel. A relay WTRU may forward data of interest to remoteWTRUs on a PC5-U plane. Relay WTRU may relay multiple eMBMS sessionsconcurrently. A relay WTRU may differentiate the priority between apacket of a first eMBMS session (e.g., associated with TMGI 1) and asecond eMBMS session (e.g., associate with TMGI 2). A Relay WTRU mayrelay eMBMS sessions and unicast sessions concurrently. Priority may bedifferentiated between an eMBMS session and a unicast session.

PC5-S messages between a remote WTRU and a relay WTRU may be utilizedfor a variety of reasons, for example, establishing a one-to-one link,obtaining IP addresses, etc. Systems, methods, and instrumentalities maybe provided for associating a PPP may be with PC5-S traffic that may notbe generated by the application layer of a remote WTRU.

A WTRU with an active IP session with an AS may lose coverage from anetwork in which the AS may reside. A WTRU may connect to a relay WTRU.The relay WTRU may designate the WTRU a remote WTRU. The remote WTRU mayobtain a different IP address that may be a link local IPv4 address. AWTRU session may not be seamlessly resumed/transitioned, for example,when the IP address changes. The remote WTRU may contact the applicationserver, for example, to inform the application server about the remoteWTRUs IP point of presence, which may be the IP address of the relayWTRU. Systems, methods, and instrumentalities may be provided for theremote WTRU to obtain the IP address of a relay WTRU (e.g., which theremote WTRU may not have information about) and pass the obtained IPaddress on to the application server, e.g., to make the session with theapplication server seamless. Identification of the relay WTRU may beuseful for the AS to track the number and identities of the remote WTRUsthat may be served by a relay WTRU. A remote WTRU may report the Cell IDof a relay WTRU without informing which relay WTRU is serving remoteWTRUs. There may be several relay WTRUs in a cell.

Priority handling (e.g., for unicast traffic) at a WTRU-to-Network relaymay be provided. A WTRU may maintain a context, for example, indicatinga ProSe link with other WTRUs. A context may be maintained, for example,in a ProSe layer. FIG. 4 illustrates an example of a ProSe layer in aWTRU. As illustrated in FIG. 4 , a ProSe layer 404 may, for example, bea separate layer above the access stratum 402 or a part of the NASentity. A ProSe layer may refer to the NAS entity in the WTRU or it mayrefer to a new separate layer or entity in the WTRU.

A WTRU may maintain information for each of the source and destinationaddress, such as a layer 2 (L2) destination address or layer 3 (L3)destination IP address, or a pair of destination L2 address anddestination IP address. Information maintained may include one or moreof a list of logical channel ID, a priority level of each ID, a keepalive timer, a set of security parameters, a maximum level of priority,a mapped EPS bearer, ProSe link IP address and port numbers, a TMGI orcell ID, or other parameters for exchange between WTRUs.

A list of logical channel ID and a priority level may be used for eachID. A priority level may be a PPP or a derived or mapped priority level.A keep alive timer may be used for a ProSe session and/or for eachlogical channel ID. A set of security parameters may be used forcommunication with a destination address.

A maximum level of priority permitted may be used for a destinationaddress or WTRU or for an application. A maximum level may bepre-configured in a WTRU. The maximum level may be obtained from theProSe Function, the application server or from a peer WTRU. The maximumlevel may be obtained via a PC5-S interface, for example, as part ofnegotiation to establish a ProSe link.

A mapped EPS bearer may indicate the packets that may be forwarded. Amapped EPS bearer may apply, for example, when a relay WTRU receivespackets on a PC5 interface from a remote WTRU, and determines to forwardthe received packets on a logical channel ID to an EPS bearer ID. A WTRUmay maintain a mapping, for example, between a (logical channel ID,priority level) and an (EPS bearer ID, QoS parameters of the EPSbearer). Such mapping may be part of a ProSe context. Asource/destination IP address, source/destination port numbers used onthe ProSe link and/or on the EPS bearer may be part of a ProSe context.

A TMGI or a cell ID or other parameters that may be exchanged betweenWTRUs, and may be part of a ProSe context. These parameters may beassociated with a ProSe link that may be used to carry messages for theexchange of parameters.

As illustrated in FIG. 4 , the ProSe layer 404 may be a separate layerabove the access stratum layer 402 or it may be part of the NAS entity.The ProSe layer 404 may be referred to as the NAS entity in the WTRU ora new entity in a WTRU.

User plane traffic within a WTRU may pass from an application clientlayer to an access stratum layer. FIG. 5 illustrates an example of aWTRU or ProSe layer when a transmission (Tx) with a new priority levelmay be requested, for example, with or without a specific destinationaddress. As illustrated in FIG. 5 , an application layer 504 may informthe ProSe layer 502 about a new priority for its packets, for example,when the application layer initiates a new transmission with a newpriority level. At 506, the application layer 504 may send a request fortransmission to a certain destination with the new priority level. At508, the ProSe layer 502, for example, upon reception of a request tosend a message 506, may verify whether there is a logical channel thatmay be using the same priority for the destination address. The ProSelayer 502 may verify, for example, whether the packet is an IP packet oris being used for other purposes, such as for a TMGI monitoring request.The ProSe layer 502 may send a message using a logical channel, forexample, when there is a logical channel with the same priority that isbeing used for the destination address. If no context, or a logicalchannel with the same priority, and optionally for the requireddestination exists, at 510, the ProSe layer may create a new context fora transmission or priority with a context. For example, the ProSe layermay create a new context when a logical channel with the same priorityis not being used for the destination address. At 512, the ProSe layer502 may inform the application layer 504 that the logical channel withthe requested priority has been granted. For example, the ProSe layer502 may inform the application layer 504 upon the confirmation of thetransmission by the lower layers or upon the reception of a response bythe ProSe layer 502 from its peer in another WTRU. At 514, the client inthe application layer 504 in a WTRU may start sending data using thepriority value received from the ProSe layer.

A ProSe layer in the WTRU may delete a ProSe context. For example, theWTRU may delete a ProSe context when a lower layer confirms that a ProSelink may no longer be feasible to maintain. The ProSe layer in the WTRUmay delete a ProSe context, for example, when a message is received torelease a session between WTRUs, e.g., for a specific logical channelidentity or for a specific priority. A WTRU may delete a ProSe context,for example, when a message is received indicating that a logicalchannel identity or a certain priority level is no longer supported orcannot be supported by a peer WTRU or one or more lower layers. A ProSelayer in the WTRU may inform the application layer or the higher layers,for example, about the deletion of the ProSe context. A ProSe layer inthe WTRU may inform the application layer about an implicit release of alogical channel or a link with the specific priority as a result of thedeletion of the context.

Systems, methods, and instrumentalities to dynamically indicate prioritybetween WTRUs may be provided. A WTRU may dynamically inform its peerabout the priority of a ProSe bearer or a ProSe link that may be or isestablished between WTRUs. The WTRU (e.g., a remote WTRU) and its peer(e.g., a relay WTRU) may be a pair of WTRUs engaged in a ProSecommunication session.

A WTRU may send a PC5-S message, for example, to inform its peer aboutthe priority associated with a ProSe link or with a ProSe bearer or withthe new logical channel that is to be created. An originating WTRU maysend a new PC5-S message to its peer WTRU, for example, for a (e.g.,every) session to be initiated or packet to be transmitted with adifferent priority but with same (source L2, destination L2) addresspair. The originating WTRU may inform the peer WTRU about the priorityassociated with a packet or a logical channel that may be configured. AWTRU (e.g., the ProSe layer in the WTRU) may send a PC5-S message when aProSe context (e.g., a new ProSe context) is created. The PC5-S messagemay include priority information, for example, a maximum priority levelthat may be supported by a WTRU (e.g., priority level per application).

The PC5-S message may include a source L2 ID (or a source higher layerapplication ID) along with a logical channel identity (LCID). The targetpeer WTRU may identify the corresponding logical channel to which theindicated priority pertains. The LCID of a logical channel may be uniquein one source/destination association. A WTRU (e.g., ProSe layer of theWTRU) may include a timer that may define the period to transmit keepalive messages associated with a corresponding logical channel and therelated priority. A WTRU may start a timer that may guard the durationin which a response may be expected. The WTRU may retransmit the PC5-Smessage, for example, if a response is not received within the duration.The WTRU may stop the associated timer and considers the procedure assuccessfully completed, for example, if a response is received.

FIG. 6 illustrates an example of a WTRU or ProSe layer sending a PC5-Smessage with priority information. As illustrated in FIG. 6 , at 602, aProSe layer may receive a request for transmission, to a destination,using a priority level (e.g., a new priority level). At 604, the ProSelayer may generate a PC5-S message to be transmitted to the indicateddestination. The message may include information about the ProSe contextparameters, for example, priority associated with a session or a logicalchannel. At 606, the ProSe layer may send the generated PC5-S message.The ProSe layer may start a timer to guard the maximum time within whicha response should be received. At 608, the ProSe layer may receive aresponse. At 608, the ProSe layer may create and/or modify a ProSecontext, and stop the timer. The ProSe layer may inform other layers(e.g., the layers above the ProSe layers) about the ProSe contextcreation and/or modification. At 610, the WTRU may start sending dataaccording to the parameters defined by the ProSe context for one or moreof a destination address, a logical channel ID, or an application ID.

FIG. 7 illustrates an example of WTRU (e.g., ProSe layer of a WTRU) thatmay receive a PC5-S message with priority information. As illustrated inFIG. 7 , at 702, the ProSe layer of a WTRU may receive a PC5 messagewith a priority level for a ProSe session. The ProSe layer may receivethe priority information for a logical channel ID, a source (e.g. layer2 or IP) address and/or an application ID. At 704, the WTRU may verifywhether a priority level can be supported, e.g., for an application ID.The WTRU may be pre-configured with different levels of priority thatcan be supported, e.g., per application or per identity of the peerWTRU, such as ProSe WTRU ID, or L2 ID or IP address used by the peerWTRU.

A relay WTRU may verify whether an indicated priority level may becorrespondingly supported on an EPS bearer. The relay WTRU may determinea mapping to an EPS bearer to a priority level. EPS QoS parameters, suchas QoS class identifier (QCI), may be derived. For example, the EPS QoSparameters may be derived to support a priority. A decision may be madewhether a new EPS bearer with such QoS profile may be established or anexisting EPS bearer may be modified and/or updated. At 706, the WTRU maycreate and/or send a response message, for example, to indicate apriority level that may be supported. A priority level indicated may bethe same or a different priority level. A WTRU may indicate a causecode, for example, to indicate why a priority level, provided with theresponse message, has been altered. As an example, a requested prioritylevel may not be correspondingly supported over the evolved packetsystem (EPS) bearer. A relay WTRU may send a PC5-S response to indicatethat the session to be established may be supported with a lowerpriority level, for example, to indicate that the EPS bearers that arecurrently active do not support the priority level requested by theremote WTRU. A relay WTRU may provide a cause code. A session to beestablished may be identified, for example, by a logical channel ID,application ID, a pair of (source, destination) L2/IP addresses and/or aset of the listed parameters.

At 708, the WTRU receiving the PC5-S message to start a new session maycreate a ProSe context. The WTRU that receives a PC5-S message to starta new session may be determined by a logical channel ID and/or for aspecific source and destination address. A ProSe context may be created,for example, after a message is responded to with a new PC5-S responsemessage. A WTRU may provide other parameters in a response, such as atimer that may be used to define when keep alive messages may be sent,for example, to maintain an active state of a ProSe context withassociated context parameters. An expiration of the keep alive timerbefore a new refresh message is received may result in a WTRU deletingthe ProSe context. At 710, the WTRU may start sending and/or receivingdata according to the parameters defined by the ProSe context.

FIG. 8 illustrates an example of establishing a ProSe session with oneor more priority levels or a ProSe context. As illustrated in FIG. 8 ,WTRU1 802 may have a priority level (e.g., a new PPP) associated with apacket to be transmitted. At 806, the application client may request theProSe layer to create and/or transmit a message with a PPP (e.g., newPPP) or priority value. The application client associated with the WTRU1802 may provide the priority level to a ProSe layer in WTRU1 802. TheProSe layer may verify whether a ProSe link or logical channel with thepriority value exists. At 808, the ProSe layer of WTRU1 802 may create aPC5-S message (e.g., a new PC5-S message) that may have informationabout a new ProSe link or logical channel to be established and theassociated priority. The ProSe layer may create the PC5-S message, forexample, when a ProSe link or logical channel with the associatedpriority does not exist. The priority may be a mapped priority or apriority level received from the application layer. The ProSe layer maycreate a ProSe context to reflect the priority level requested by theapplication layer. At 810, the ProSe layer may send the PC5-S message toa destination WTRU, WTRU2 804. For example, the PC5-S message ma includeinformation about the ProSe context or a priority level and a logicalchannel ID.

At 810, WTRU2 804 may receive the PC5-S message from WTRU1 802. At 812,WTRU2 804 may process and verify contents of the message including thepriority information. For example, WTRU2 804 may verify whether anindicated priority level may be handled by the WTRU (e.g., mapped to anallowed EPS bearer associated with a QoS). At 814, WTRU2 804 maydetermine the supported priority value, and may create a ProSe contextfor a logical channel. WTRU2 804 may modify the supported prioritylevel. At 816, WTRU2 804 may respond with a PC5-S message. The PC5-Smessage may indicate a supported priority level that can be handled.

At 816, WTRU1 802 may receive a PC5-S message from WTRU2 804. The PC5-Smessage may be received by WTRU1 802 in response to a previous messagesent at 810, with contents indicating a supported priority level. At818, WTRU1 802 may stop the timer previously started. WTRU1 802 maymodify a corresponding ProSe context according to the indicated prioritylevel and indicated logical channel. WTRU1 802 may inform the upperlayers that a priority level has been granted. At 820, WTRU1 802 mayengage with its peer WTRU, WTRU2 804 in ProSe communication, forexample, according to the exchanged ProSe context.

The priority level information exchange between two WTRUs as describedherein may be applicable to a case where a group of WTRUs arecommunicating via a ProSe layer. For example, a priority level for ProSecommunication may be exchanged between two or more WTRUs, such as agroup of WTRUs communicating using ProSe. A WTRU may send a PC5-Smessage to a group. A WTRU may indicate in message content that apriority indication or a request to modify a priority applies to thegroup. For example, a relay WTRU may seek to inform each of the remoteWTRUs that it can no longer support the handling of a priority level orthat it can support (e.g. only support) a maximum level of priority. Therelay WTRU may send a PC5-S message, for example, to indicate a maximumpriority level that can be supported and applied to each of the remoteWTRUs. A PC5-S message from a relay WTRU may include informationindicating message applicability to each of the remote WTRUs. A PC5-Smessage may include, for example, one or more of a Group ID, an IPaddress used by the group, a service ID, ProSe relay service code, or adestination L2 address used by the group. A PC5-S message may be sent toa group of remote WTRUs, for example, by using a destination L2 addressused by a group. A WTRU may engage in a behavior (e.g., take the sameactions) as discussed herein, for example, when a WTRU sends a PC5-Smessage to an individual peer WTRU.

A WTRU, that may be part of a group, may receive a PC5-S message. ThePC5-S message may be addressed to the group of which the WTRU may be apart. The message may include a request to modify a ProSe context orpriority used for communication with a source WTRU. The message mayinclude a maximum level of priority that may be used by a receivingWTRU. The WTRU may modify its ProSe context accordingly or modify apriority used to communicate with a source WTRU accordingly. The WTRUmay engage in behavior (e.g., take actions) as described herein whenreceiving a PC5-S message to modify a priority or ProSe context. A WTRUmay respond to indicate the status of a request. A WTRU may informhigher layers about a change in priority level for communication.

The priority of a logical channel may be incorporated within a MACheader, e.g., along with LCID. A receiving peer WTRU may be able toextract the priority level associated with a (e.g. each) logical channelidentified by LCID, for example, when the receiving peer WTRU isde-multiplexing different logical channels from a received MAC PDU.Priority information may be provided to the upper layers in a WTRU(e.g., ProSe and/or NAS layer(s)). Upper layers may use the priorityinformation to determine that corresponding data from a logical channelis carried onto an EPS bearer. QoS profile of the EPS bearer may satisfyor meet the indicated priority of incoming ProSe data at relay WTRU.

Systems, methods, and instrumentalities may be provided to modify (e.g.,dynamically modify) priority between WTRUs. For example, the prioritymay be modified when a WTRU is incapable of handling a priority level.For example, a relay WTRU context may include a mapping from a PC5logical channel ID to an EPS bearer ID. This mapping may be based on thepriority of the PC5 logical channel ID. The relay WTRU may have too muchdata to handle from one or more WTRUs, for example, at a certainpriority level. The relay WTRU may have an EPS bearer deactivated, whichmay make the handling of PC5 traffic at a certain priority infeasible.The relay WTRU may send a PC5-S message to its peer WTRU, for example,to communicate the changes in its capability to handle traffic for acertain priority. The message may comprise a modified priority levelthat may be supported for at least one identified logical channel ID.The message may further comprise a cause code indicating a reason for amodification and/or a timer that specifies a duration for which therecipient may not be allowed to request another priority level or ahigher priority level for the identified channel or one or more logicalchannel IDs. The relay WTRU may modify corresponding ProSe contextbefore or after sending the PC5-S message. Modifying a ProSe context mayinvolve changing parameter values (e.g., priority values) associatedwith a ProSe context or deactivating a ProSe context. Deactivating mayresult in deleting a ProSe context and the configuration used by theProSe context. The relay WTRU may start a timer, for example, whensending the message. The timer may indicate a time (e.g. a maximum time)for a response. A WTRU may stop a timer, for example, when a response(e.g., a PC5-S response message) is received. The relay WTRU may send arequest to modify a priority of a ProSe link, for example, when it canno longer act as a relay.

FIG. 9 illustrates an example of a WTRU (e.g. a relay WTRU) or ProSelayer in the WTRU sending a new PC5-S message with modified priorityinformation. As illustrated in FIG. 9 , at 902, one or more of thefollowing may occur: a capability of a WTRU (e.g., a relay WTRU) maychange, one or more EPS bearers may be modified, or the WTRU may becongested. At 904, a ProSe layer of the WTRU may create a PC5-S message(e.g., a new PC5-S message). The PC5-S message may include a modifiedpriority level. The priority level may be modified for one or more oflogical channel IDs. A priority level may be supported for each of thelogical channel IDs. At 906, the ProSe layer may send the PC5-S message.The ProSe layer may start a timer. The timer may be run for a durationwithin which a response to the message sent may be received by the WTRU.At 908, the ProSe layer may receive a response. Accordingly, the ProSelayer may stop the timer and create and/or modify the ProSe context. TheProSe layer may inform one or more higher layers within the WTRU aboutsuch change. At 910, the WTRU may start handling data according to theparameters defined by the ProSe context. The ProSe context may be forone or more of a destination address, a logical channel ID, or anapplication ID. A PC5-S message may lead to modification of the Priorityof a ProSe Link. Modification may occur, for example, when a WTRU (e.g.,a relay WTRU) or ProSe layer cannot handle packets with a certainpriority from one or more WTRUs.

A WTRU may receive a PC5-S message to modify the priority related to aProSe link or a logical channel ID. A WTRU may modify its ProSe contextaccording to a received modification request. In an example, a WTRU maydelete a ProSe context and/or use a different priority level (or logicalchannel ID) for the packets allocated to this logical channel. The ProSelayer in the WTRU may inform the application layer that a certainpriority level is no longer supported. The ProSe layer may provide amaximum priority level (e.g. PPP) that can be supported. An applicationclient in a WTRU may start using priority levels within the supportedrange. The ProSe layer in a WTRU may respond with a PC5-S message, forexample, to inform a peer WTRU that a ProSe context has been modified orthat the priority level of a logical channel ID has been modifiedaccordingly.

FIG. 10 illustrates an example of modifying a ProSe context or priorityfor a ProSe Link or communication between two WTRUs, WTRU1 1002 andWTRU2 1004. The ProSe context or priority for a ProSe Link orcommunication may be for one or more logical channel IDs. As illustratedin FIG. 10 , at 1006, a ProSe communication may be ongoing between WTRU11002 and WTRU2 1004. The ongoing ProSe communication may be based on apreviously established ProSe context and/or priority. At 1008, changesmay occur in one or more of the following: capability, load level, orEPS bearer of WTRU2 1004. For example, the EPS bearer may be modified ordeactivated. At 1010, WTRU2 1004 may create a PC5-S message (e.g., a newPC5-S message) that may request a modification to an established ProSelink with a priority or a ProSe context. At 1012, WTRU2 1004 may sendthe PC5-S message requesting modification of the priority (or ProSecontext) to WTRU1 1002. The message may include the information and orthe ProSe context to be used for modification. At 1014, WTRU1 1002 mayreceive the message. At 1016, WTRU1 1002 may modify its ProSe contextaccording to the received information and/or ProSe context. WTRU1 1002may inform its higher layers about the modified priority and/or ProSecontext. At 1018, WTRU1 1002 may create a PC5-S response message toindicate the status of the request to modify a ProSe context and/or apriority value. At 1020, WTRU1 1002 may send the response message toWTRU2 1004. The response message may inform WTRU2 1004 about the statusof the request. At 1022, the ProSe communication between WTRU1 1002 andWTRU2 1004 may be resumed according to the modified ProSe context and/orpriority value.

Systems, methods, and instrumentalities may be provided to determine apriority value of a ProSe link and mapping it to an EPS bearer. Apriority level (e.g., as indicated in a PC5-S message with priorityinformation or in a MAC header received by a relay WTRU) may be used asis or may be mapped to a PC5 ProSe priority level. A relay WTRU maydetermine an appropriate EPS bearer QoS to support a PC5 ProSe priority.

An EPS bearer QoS may be determined at a relay WTRU, for example, basedon a mapping between PC5 ProSe priority and EPS QoS profile. Forexample, the EPS bearer QoS may be determined using parameters such asQCI, Allocation and Retention Priority (ARP), etc.

The EPS bearer QoS may be determined at a relay WTRU. For example, theEPS bearer QoS may be determined based on a clear mapping between PC5ProSe priority and the Priority QoS attribute of the EPS bearer's QCI. APC5 ProSe priority level may be mapped to one of the following: apriority of the non-Guaranteed Bit Rate (non-GBR) EPS bearers, such asEPS priorities 1, 7, 6, 8 and 9 with QCIs 5, 6, 7, 8 and 9,respectively, or to EPS priorities/QCIs (e.g. not only limited tonon-GBR bearers). The PC5 ProSe priority level may be mapped, forexample, when a guaranteed bit rate is not specified for a ProSe PC5link/session (e.g., no QoS support for ProSe). ProSe PC5 priority to EPSpriority/QCI mapping may be based on decision boundaries with specifiedranges/thresholds, such that a particular range of PC5 priorities map toa given EPS priority value.

A ProSe may support QoS parameters including, for example, ProSeguaranteed bit rate, ProSe packet delay, ProSe packet loss, etc. TheseQoS parameters may be provided in a PC5-S message, for example, alongwith priority information. A PC5 priority level may be mapped to apriority of Guaranteed Bit Rate (GBR) EPS bearers, such as QCIs 1, 2, 3and 4 with EPS priorities 2, 4, 5 and 3, respectively. QoS bearercharacteristics may be selected to satisfy indicated PC5 QoS parameters.

Mappings from PC5 ProSe priorities to EPS QoS profiles or EPSQCIs/priorities may be static. These mappings may be based on apre-determined relationship. The pre-determined relationship may belocally preconfigured at a relay WTRU, for example, in the mobileequipment (ME), universal subscriber identity module (USIM) ProSeconfiguration information or via ProSe management objects pushed to theWTRU via Open Mobile Alliance (OMA) Device Management (DM).

Mappings from PC5 ProSe priorities to EPS QoS profiles or EPSQCIs/priorities may be dynamic. For example, mappings from PC5 ProSepriorities to EPS QoS profiles or EPS QCIs/priorities may be assigned bya network. Such assignment may depend on the network's overallresources, WTRU's allowed and allocated bearer resources, etc. Forexample, a relay WTRU may contact a network node (e.g., an MME or aProSe Function) to retrieve a mapping (e.g., upon reception of a PC5-Smessage with priority information). Mapping may be provisioned on a WTRUby a ProSe function, for example, during ProSe authorization.

A relay WTRU may determine the EPS QoS parameters (e.g., QCI) to satisfythe PC5 ProSe priority/QoS. A relay WTRU may check whether an EPS bearerwith a QoS/QCI already exists or a new EPS bearer is to be established.

An established EPS bearer with a QoS/QCI may exist that may handle thePC5 ProSe priority. A relay WTRU may request update regarding uplinktraffic flow templates (TFTs) for the active default or dedicated bearerwith matching QoS. For example, the relay WTRU may request the updatefrom a packet data network gateway (PGW). The relay WTRU may request theupdate to manage and/or steer ProSe traffic flows that may have similarQoS/QCI handling. A relay WTRU may initiate a WTRU requested bearerresource modification. The bearer resource modification may triggerbearer modification without a bearer QoS update.

A relay WTRU may choose to establish a new dedicated bearer with anappropriate QoS/QCI profile, for example, if no EPS bearer with anappropriate QoS/QCI is available. For example, the new dedicated bearermay be established by triggering WTRU requested bearer resourcemodification. Triggering of bearer resource modification may invoke adedicated bearer activation for establishing a new dedicated bearer withan appropriate QoS/QCI based on required value.

As illustrated in FIG. 7 , a relay WTRU may create a ProSe context, forexample, when a ProSe priority is mapped to an EPS bearer, the EPSQoS/QCI are determined, and the EPS bearer is established or modifiedbased on the determined EPS QoS/QCI parameters. The ProSe context may becreated based on information about mapped EPS bearer on which packetsmay be forwarded, for example, mapping between a (logical channel ID,priority level) and an (EPS bearer ID, QoS parameters of the EPSbearer). The relay WTRU may send a response message to its peer WTRU toconfirm the PC5 ProSe priority level that can be supported. A relay WTRUin downlink may engage in the foregoing behavior, for example, when itreceives downlink data destined to a remote WTRU from eNB on a given EPSbearer. The relay WTRU may determine the associated PC5 logical channelto which an EPS bearer may map to. The relay WTRU may determine theassociated PC5 logical channel, for example, when the EPS bearer ID of abearer (e.g., with its corresponding QoS parameters), matches a mappedEPS bearer in a ProSe context that is maintained by the relay WTRU.

A relay WTRU may apply a reverse mapping of EPS QoS/QCI to PC5 ProSepriority to determine the appropriate PC5 logical channel, for example,if an EPS bearer ID does not exist in any of the relay WTRU's ProSecontexts or the same EPS bearer is mapped for one or more PC5 logicalchannels. For example, two different PC5 logical channels map to thesame EPS bearer.

Reverse mapping may be statically or dynamically assigned as discussedherein. A relay WTRU may determine whether a new PC5 logical channelwith determined PC5 priority should be established or whether anavailable PC5 logical channel exists and can be used. The relay WTRU maymake such determination based on a determined PC5 ProSe Priority.

A relay WTRU may be configured with mapping information that maps an EPSbearer with a QoS to at least one PC5 ProSe priority level. Mappinginformation may comprise mapping from an EPS bearer with a QoS to a list(or range) of ProSe PC5 priorities. A WTRU may determine the PC5priority level or range of priority levels that may be used, forexample, when the WTRU receives data on an EPS bearer with a QoS. A WTRUmay choose a highest or lowest priority based on its load conditions,for example, when there is a mapping to more than one levels.

An EPS QoS (e.g., Q1) may map to a range of values of PC5 ProSepriorities less than a value (e.g., a possible priority level P). Datamay be received on an EPS bearer with a QoS. A WTRU may map data to aPC5 priority level P or below, for example, when the WTRU receives dataon an EPS bearer with a QoS. The WTRU's mapping of the received data toa PC5 priority level P may depend on whether a logical channel withpriority level P exists and/or the load conditions of the WTRU.

FIG. 11 illustrates an example of a relay WTRU or a ProSe layerreceiving and/or processing a new PC5-S message with priorityinformation and determining appropriate EPS bearer mapping. Asillustrated in FIG. 11 , at 1102, a relay WTRU may determine PC5 ProSepriority based on indicated priority information received in a PC5-Smessage. At 1104, the relay WTRU may determine whether bearer QoS (e.g.,QCI) supports the PC5 ProSe priority. At 1106, the relay WTRU may decideto establish a new EPS bearer with determined EPS bearer QoS or modifyan existing bearer with the same QoS. At 1108, the relay WTRU may createProSe context with information about mapped EPS bearer and send aresponse message to confirm the ProSe priority to be supported.

A WTRU may map or use a lower priority or an EPS bearer with a lower QoSpriority relative to the received priority, for example, if the WTRUcannot support the received priority or the mapped priority or may notsupport bearer modification or bearer activation. The WTRU may not beable to modify a bearer or activate a bearer, for example, due to arejection from the network or existing pre-configuration. The WTRU mayuse a selected EPS bearer. The WTRU may modify the ProSe context. Themodified ProSe context may include mapping between the ProSe link orlogical channel and priority and selected EPS bearer. The WTRU maymodify the ProSe context, for example, to reflect the selection andmapping as described herein.

The WTRU may respond to or inform other WTRUs about a modified prioritylevel, for example, using a PC5-S signaling message. The PC5-S messagemay comprise a cause code to indicate a reason for modifying a priority.

Systems, methods, and instrumentalities for handling MBMS data at aWTRU-to-Network relay may be provided. An MBMS session priority levelmay be provided by a network. A relay WTRU that supports MBMS relayingmay receive a service/session priority description/indication. Theservice/session priority description/indication may be received in anMBMS service announcement message from the service provider. Forexample, a priority description/indication may be associated with a TMGIin the user service description (USD) metadata.

A service provider may assign priorities for various MBMSservices/sessions, for example, based on the nature ofservices/sessions. For example, a public safety related MBMS service maybe assigned a higher priority over an entertainment service. A voicesession may be assigned higher priority over a video session. The numberof levels of MBMS service/session priorities and priority orders may berepresented by a priority level number. For example, eight prioritylevels may be provided. For example, priority level 1 may be higher thanpriority level 2, and so on. A service announcement with missingpriority information of an MBMS service/session may be considered ashaving lower priority than service announcements having explicitpriorities.

FIG. 12 illustrates an example of determining priority of multimediabroadcast multicast services (MBMS) data. As illustrated in FIG. 12 , at1212, an evolved node B (eNB) or a multi-cell/multicast coordinatingentity (MCE) 1206 may receive MBMS enhanced radio access bearer (E-RAB)QoS parameters from a mobility management entity (MME) 1208. At 1214,the eNB or MCE 1206 may determine/derive a priority for an MBMS session,for example, based on the MBMS E-RAB QoS parameters received from theMME. The parameters may be received over an M3 interface. An eNB or anMCE may derive (e.g., directly derive) a priority for an MBMS sessionfrom an Allocation and Retention Priority (ARP) in QoS parameters.MBMS-SessionInfo (e.g., as provided by an eNB) may comprise a prioritylevel. An eNB may derive priority information, for example, usingoperations and maintenance (O&M) procedures. An eNB may receive priorityinformation from an MME or an MBMS infrastructure in a network, such asan MBMS node in the network.

At 1216, relay WTRU 1204 may receive MBSFNAreaConfiguration from eNB/MCE1206. Relay WTRU 1204 that supports MBMS relaying may read a priorityindication associated with a specific TMGI, for example, from thereceived MBSFNAreaConfiguration broadcast in a multicast control channel(MCCH). An MBMS-SessionInfo element of the MBSFNAreaConfiguration may beextended to provide a priority indication, for example, according to thefollowing example:

MBMS-SessionInfo-r9 ::= SEQUENCE {  tmgi-r9 TMGI-r9,  sessionId-r9 OCTETSTRING (SIZE (1)) OPTIONAL, -- Need OR  logicalChannelIdentity-r9INTEGER (0..maxSessionPerPMCH-1),  priority INTEGER (0..7)  ... }

At 1218, relay WTRU 1204 may use the received MBSFNAreaConfiguration todetermine an appropriate PC5 priority level. The determined PC5 prioritylevel may be mapped from a received (or read) priority level. Relay WTRU1204 may be configured to perform mapping and/or to use a read orreceived priority level. Relay WTRU 1204 may create a ProSe context, forexample, according to parameters or a sub-set of the parameters, e.g.,parameters used to define or maintain ProSe communication context. RelayWTRU 1204 may verify its ProSe contexts, for example, when the WTRUreceives data for an MBMS service (or TMGI). Verification may beperformed, for example, to determine the PC5 logical channel, the WTRUmay use for forwarding MBMS data on the PC5 link. A ProSe context maycomprise information, such as a mapping between a TMGI and a ProSe link(or logical channel ID and/or other parameters). At 1212, relay WTRU1204 may use the derived or determined PC5 per packet priority totransmit MBMS data over PC5 link. At 1220, the WTRU 1204 may receiveMBMS, for example, from a MBMS gateway 1210. At 1224, relay WTRU 1204may forward MBMS data to one or more remote WTRUs 1202. The relay WTRU1204 may forward MBMS data on the determined ProSe link or with adetermined priority level associated with a TMGI.

A relay WTRU that supports MBMS relaying may send a query message to anMME for QoS parameters of one or more MBMS sessions (e.g., TMGIs). AnMME may return the QoS information it has assigned to one or moresessions. A Relay WTRU may derive a priority for the MBMS sessions, forexample, based on received QoS parameters. A relay WTRU may query theARP assigned to an MBMS session. A Relay WTRU may use received ARPinformation to derive a priority level.

A relay WTRU that supports MBMS relaying may send a query message to aProSe function to query priority information for one or more MBMSservice/sessions. The relay WTRU may send the query message via a PC3interface. The query message may include an MBMS service description andidentification, for example, to permit the ProSe Function to determinethe application server that provides the service and identify theservice in question. A ProSe function may determine the applicationserver, e.g., based on the query message, and may forward the query tothe server. The ProSe function may forward the query via a PC2interface. A ProSe function may forward a response received from anapplication server to a relay WTRU that initiated the query.

An MBMS session priority level may be provided by a WTRU to other WTRUs.Other ProSe WTRUs, e.g., remote WTRUs, may proactively send the priorityof MBMS service/sessions (e.g., as identified by a TMGI) that the remoteWTRUs are interested in. The priority level information for a specificTMGI or other parameters that may be used to determine MBMS priority maybe sent in a PC5-S (e.g., a new PC5-S) signaling message. For example, aTMGI monitoring request message may be used. Priority levels may beexplicit or implicit. For example, a signaling message or a TMGImonitoring request message from a remote WTRU may include a prioritylevel associated with a TMGI. A priority may be implicitly derived. Forexample, the priority may be derived by a relay WTRU from the priorityof a received PC5-S signaling message to setup a broadcast session. Thesignaling message may be a TMGI monitor request message. A relay WTRUmay use the PPP, priority or LCID, for example, when it sends the eMBMStraffic on the PC5 one to many link. A remote WTRU may receive theinformation, for example, in the user services description (USD) or aspart of application layer signaling. A WTRU may send a message, forexample, upon a change of priority associated with a TMGI.

FIG. 13 illustrates an example of a relay WTRU receiving a ProSe perpacket priority level information associated with a TMGI. As illustratedin FIG. 13 , at 1308, remote WTRU1 1302 may receive a serviceannouncement message. The remote WTRU1 1302 may receive the serviceannouncement message from an application server. The serviceannouncement message may include a priority level associated with aTMGI, e.g., TMGI X. At 1310, the remote WTRU2 1304 may receive a serviceannouncement message. The service announcement message may includepriority level information associated with another TMGI, e.g., TMGI Y.Each of the remote WTRUs may derive MBMS priority from the receivedpriority level information associated with each of the TMGIs. At 1312,the remote WTRUs 1302 and/or 1304 may proactively send derived MBMSpriority to the relay WTRU 1306. The MBMS priority may be the ProSe perpacket priority level. At 1314, the relay WTRU 1306 may request remoteWTRUs 1302 and/or 1304 to send MBMS priority.

As illustrated in FIG. 13 , at 1316, remote WTRU1 1302, via a message(e.g. a PC5-S message), may send priority level information associatedwith TMGI X to the relay WTRU 1306. At 1318, remote WTRU2 1304, via amessage (e.g. a PC5-S message), may send priority level informationassociated with TMGI Y to the relay WTRU 1306. The priority levelinformation may be MBMS priority. The message used by the remote WTRUmay be a PC5-S (e.g., a new PC5-S message) or a TMGI monitoring requestmessage.

As illustrated in FIGS. 13 , at 1320 and 1322, relay WTRU 1306 may senda request messages to remote WTRUs remote WTRU1 1302 and remote WTRU21304, for example requesting a proper priority of the MBMSservice/sessions as identified by a TMGI. The relay WTRU may send therequest messages via a PC5 broadcast channel to one or more remoteWTRUs. The relay WTRU may send the request messages via PC5-S messagesto one or more remote WTRUs, for example the remote WTRUs that may havea one-to-one link established with the Relay WTRU.

Remote WTRUs WTRU1 1302 and WTRU2 1304, upon receiving a request fromthe relay WTRU 1306, may contact an application server or a ProSefunction to obtain a priority level associated with a TMGI. Asillustrated in FIG. 13 , remote WTRUs WTRU1 1302 and WTRU2 1304 at 1324and 1326 respectively may respond to a requests 1320 and 1322 withresponse messages. The response messages may be PC5-S messages (e.g.,new PCS-5 messages) or MBMS priority response messages. The responsemessages may indicate the priority of the MBMS service/sessions (asidentified by the TMGI) to the relay WTRU.

At 1328, the relay WTRU 1306 may store the received MBMS priority valuesfor MBMS sessions. The relay WTRU 1306 may map the priority levels toPC5 per packet priority values. At 1330, relay WTRU 1306 may detect MBMSdata associated with TMGI X or TMGI Y. At 1332, relay WTRU 1306 may usethe MBMS priority received from the remote WTRUs or the mapped PC5 perpacket priority to transmit the MBMS data related to the detected TMGIto one or more remote WTRUs. A1334, the relay WTRU 1306 may send theMBMS data via a PC5 interface to one or more remote WTRUs.

A remote WTRU may send a new or existing PC5-S message to inform one ormore other WTRUs about the received priority information indicating apriority level. The remote WTRU may send the PC5-S message uponreceiving a new or modified priority information for MBMS service ordata (e.g., as identified by a TMGI). The remote WTRU may proactivelysend the PC5-S message indicating the priority level information. Apriority level may be a mapped priority level or a priority levelreceived from an application layer or other network nodes. The networknodes may include an MME or a ProSe function.

A relay WTRU may broadcast an indication, e.g., together with a TMGIadvertisement message. A remote WTRU that observes the indication maysend the MBMS service/session priority information to the Relay WTRU,for example, as described herein.

A remote WTRU may determine the priority level associated with an MBMSservice/session. For example, the priority may be determined based onpre-configured information. A WTRU may be configured with a prioritylevel per TMGI. A remote WTRU may determine the proper priority for anMBMS service/session, for example, based on priority information inreceived service announcement messages. A WTRU (e.g., a remote WTRU) maydetermine a priority for a DL MBMS data priority, for example, based ona priority indication received from its application layer for theunicast UL data of the same service/group.

A relay WTRU may receive the priority information from a ProSe functionor an MME. The relay WTRU may receive the priority information directlyfrom the ProSe function or the MME. New messages or existing messagesmay be used to carry such information. A relay WTRU, for example, uponreceiving the priority information, may create or modify a ProSecontext. The ProSe context may be created, for example, so that a TMGIdata or service may map to a PC5 ProSe link with a priority handlinglevel.

A WTRU may determine a priority of an MBMS session/service. The WTRU maydetermine the priority information locally. A WTRU (e.g., a relay WTRU)that supports MBMS relaying may have a preconfigured list of MBMSservices with an associated priority level assigned for handling on aPC5 ProSe link. The MBMS services may be identified by a TMGI. MBMSservices may be identified, for example, by a globally unique serviceID. A relay WTRU may look up the list to get the assigned priority. Forexample, the relay WTRU may look up the list on receiving a serviceannouncement message with a service ID. A service ID that is notpreconfigured in the WTRU may be considered lower priority thanconfigured service IDs. A relay WTRU may obtain the priority informationfrom an MME, ProSe function or an application server for which it may berelaying data. The relay WTRU may obtain this information directly fromthe MME or the ProSe function.

A WTRU, e.g., a relay WTRU may determine priority level of an MBMSsession/service from an uplink unicast session data. MBMS data forwardedby a relay WTRU may be for public-safety applications, such as a grouppush-to-talk service. A remote WTRU that listens to the DL MBMS dataforwarded by a relay WTRU may send uplink data to the applicationserver. The DL MBMS data may be ProSe one to many communication. Theapplication layer in a remote WTRU may provide PPP for uplink unicastdata. A relay WTRU may receive uplink unicast data from the remote WTRU.The relay WTRU may establish mapping between one or more of the PPP,LCID, the priority, or the IP tuples of the related application, forexample, as described herein. Such mapping information may be stored inthe context of the remote WTRU. A relay WTRU may derive the PPP, LCID,priority, etc. from a previously established mapping, for example, whenthe relay WTRU subsequently receives the MBMS traffic from the sameapplication server. The PPP, LCID, priority, etc. may be used, forexample, to schedule the transmission on a PC5 interface.

In an example, a relay WTRU may receive, from a remote WTRU uplink,packets destined for an application server with a destination IP addressand port. The relay WTRU may learn that the PPP, LCID, priority, etc. ofthe data. The relay WTRU may establish a mapping betweenDest_IP_Addr/Port_PPP, LCID, priority, etc. The relay WTRU may receiveMBMS data that has the source IP address and port that are identical tothe stored Dest_IP_Addr/Port. The relay WTRU may use the learned PPP toforward the MBMS data to one or more remote WTRUs. For example, therelay WTRU may forward the MBMS data over a PC5 link.

A relay WTRU may send the same or similar traffic in the downlink on aone to one communication PC5 interface, for example, before relayingMBMS traffic. A relay WTRU may store the last PPP, priority value orLCID used to send the traffic to the remote WTRU. The last storedunicast PPP, priority or LCID may be used to transmit MBMS broadcasttraffic, for example, when the relay WTRU starts transmitting the MBMStraffic on a PC5 one to many link.

An MBMS service/session priority may be mapped to a PC5 transmissionpriority. A relay WTRU may receive service/session priorities related toMBMS data it may relay from the network or remote WTRUs. A Relay WTRUmay be pre-configured with a mapping (e.g., a fixed mapping) betweenservice/session priorities and PC5 per packet priorities. The relay WTRUmay map the MBMS service/session priorities to one or more PC5 perpacket priorities. Mapping may or may not be one-to-one mapping. Anumber of priority levels may be different. Multiple service/sessionpriorities may be mapped to a (e.g. the same) PC5 per packet priority.

Systems, methods and instrumentalities to determine priority handlingfor PC5-S traffic may be provided. Techniques to determine a priorityassociated with a PC5-S message may be provided. PC5-S signaling may beinitiated by a ProSe layer of a remote WTRU. For example, the signalingmay be initiated upon receiving a trigger from an application layer inthe WTRU. An upper layer application may trigger a ProSe layer toinitiate one to one direct communication, for example, by passing to theProSe layer a destination ID, e.g., a Layer-2 Destination ID, or ahigher layer destination ID of a peer WTRU. A trigger message, e.g.,provided by an application layer, may comprise a priority levelinformation associated with the trigger message to the ProSe layer inthe WTRU. A ProSe layer may determine the priority of each PC5 signalingmessage, for example, based on the priority level information orpriority. A determined priority may be a PPP or a mapped priority level,for example, mapped from a PPP. The priority provided by an applicationlayer may be a PPP or any other priority associated with the request.

A priority may be indicated to a ProSe layer by one or more ways asdescribed herein. A priority may be indicated to a ProSe layer, forexample, by indicating a level (e.g., from 1 to x) to a ProSe layer. Inan example, 1 may be a highest priority application and x may be alowest priority application.

A priority may be indicated to a ProSe layer, for example, by indicatingan explicit application/request type to the ProSe layer in the WTRU,e.g., emergency, public safety, non-public safety, police application,etc.

A priority may be indicated to a ProSe layer, for example, by providingan application ID in a trigger message. The ProSe layer may be able toderive a priority from an application ID received from an applicationlayer. Mapping between an application ID and a determined priority(e.g., for transmission of a PC5-S message) may be pre-configured in theWTRU, obtained from the ProSe Function or obtained from the applicationserver.

A priority level of PC5-S messages may be determined by the ProSe layer,for example, based on a priority received from an application layer. AProSe layer may pass the priority of the PC5-S message to the accessstratum or lower layers, e.g., as illustrated in FIG. 14 .

FIG. 14 is an example of handling priority for a PC5-S message. Asillustrated in FIG. 14 , a ProSe layer 1404 may pass a PC5-S packet froman application layer 1402 to the access stratum 1406. A separate logicalchannel may be created and the ProSe context may be updated in the ProSelayer at the access stratum for sending signaling packets, for example,when a logical channel with the same priority does not already exist.PC5-S and PC5-U (e.g., signaling and data) packets may be sent on alogical channel. The packets may be sent on the same logical channelwhen they have the same priority level.

A ProSe layer may employ a fixed mapping between a priority levelreceived from an application and a priority level (e.g., a PPP or amapped priority) of the PC5-S message. PC5 messages originating due to atrigger from a particular application (e.g., as determined by anapplication ID or application type) may have the same determinedpriority value. For example, an application may indicate emergency orother highest priority level to the ProSe layer. An indicated level maybe mapped to a PC5-S priority level 1 at the ProSe layer. For example,the indicated level may be mapped based on the mapping information inthe WTRU (e.g., locally in the WTRU). A priority may be determined forthe application and may be used for subsequent PC5 messages. As anexample, subsequent PC5 messages that may be triggered by theapplication e.g. by (ID or type), such as a direct communicationrequest, security parameter exchange message, keep alive, etc., may betransmitted with the same priority level, e.g. level 1 in this example.

Each of PC5-S message types may have a priority level (e.g., a differentpriority level) associated with it. The associated priority levels maybe configured in the ProSe layer. As an example, a direct communicationrequest message may be configured to have a priority level. A PC5-Smessage may have a higher priority than another PC5-S message type, suchas a link keep alive message or other PC5-S message type. A ProSe layermay have a pre-configured determined priority for another PC5-S message,such as a TMGI monitoring request message. A ProSe layer or the WTRU mayhave a list of PC5-S messages with an ordered priority level. As anexample, a first entry in a list may be considered to have a highestpriority or may have an explicit priority number. A lowest entry in thelist may be considered to have a lowest priority or may have an explicitpriority number.

Priority of a PC5-S message may be determined, for example, using acombination of techniques. As an example, a priority of a PC5-S messagemay be determined using a type of (PC5-S) message requested to be sentand the Application ID/type that triggers the request.

FIG. 15 illustrates an example of determining a priority level fortransmitting a PC5-S message. As illustrated in FIG. 15 , one or moreinputs may be used to determine a priority level of a PC5-S message. Asillustrated in FIG. 15 , an application X 1502 may send a trigger PC5-Sto the ProSe layer 1504. The trigger message may include a priority ofapplication ID of the PC5-S message type. ProSe layer 1504 may receive atype of PC5-S message 1506 from a peer WTRU. At 1508, the ProSe layer1504 may determine priority of the PC5-S message according to one ormore factors and/or inputs. The ProSe layer 1504 may verify whether alogical channel with a determined priority exists for a destinationWTRU. The ProSe layer 1504 may request that lower layers (e.g., theaccess stratum 1510) create a logical channel with a determinedpriority, for example, when a logical channel with a determined prioritydoes not exist. At 1510, the ProSe layer 1504 may provide the lowerlayers the PC5-S message with the determined priority level.

A WTRU may obtain mapping information from a ProSe Function or from anetwork node, e.g., MME. One or more messages may be defined on aninterface used to obtain the information, such as an interface between aWTRU and ProSe function (e.g., a PC3 interface) or between a WTRU and anMME (e.g., using NAS protocol). A WTRU may request an MME or a ProSefunction for mapping or priority information, for example, when a newPC5-S message is received for which the WTRU does not have informationto determine the priority level.

Priority information for a PC5-S message may be determined, for example,by preconfiguring the priority levels for different PC5-S messages. Forexample, the priority may be preconfigured in a universal subscriberidentity module (USIM) ProSe configuration information. The priorityinformation may be obtained via ProSe management objects pushed to theWTRU, for example, via open mobile alliance (OMA) device management(DM).

Information may be provided by the ProSe function on a per public landmobile network (PLMN) basis. One or more PLMNs may configure WTRUs withdifferent priority levels/PPP levels for each PC5-S message. A ProSelayer may pass on a corresponding preconfigured priority level for amessage to the access stratum layer in the WTRU, for example, when theProSe layer generates a PC5-S message.

FIG. 16 illustrates an example of updating a PPP value of PC5-S messagesbased on a new highest PPP of a PC5-U transmission. As illustrated inFIG. 16 , at 1602 the ProSe layer may keep track of the highest PPP fora PC5-U transmission. At 1604, the ProSe layer may determine thepriority of the PC5-S message. For example, the priority of the PC5-Smessage may be determined according to one or more factors/inputs. At1606, the ProSe layer updates the PPP value for a PC5-S message with thehighest PPP for PC5-U message. The priority of a PC5 message may bedetermined based on the highest PPP value used by a WTRU for PC5-Utransmission. The highest PPP value of PC5-U transmission may be used,in a number of ways, to determine the PPP or priority of PC5-S messages.Several examples of using the highest PPP value of PC5-U transmission tomake a PC5-S priority determination are described herein.

A protocol layer, for example, a ProSe Protocol layer, a non-accessstratum (NAS) layer, or a radio resource control (RRC) layer may keeptrack of the highest PPP value used for PC5-U transmission. The highestPPP value for user plane transmission (e.g., a PC5-U transmission) maybe tracked and used as the PPP value for each of the PC5-S messages. Forexample, a WTRU may transmit user plane packets with priorities fromPPP-2 to PPP 7, where PPP-2 is the highest priority in this example. Inan example, PC5-S messages may use the highest available PPP (e.g.PPP-2) for PC5-S messages. A priority range for user plane packets maychange to PPP 1 to PPP 7, where PPP 1 is the new highest user planepriority value. In an example, PC5-S messages may be sent with the newavailable highest user plane PPP value (e.g. PPP-1), as illustrated inFIG. 16 .

A ProSe layer may use a range of possible PPP values for different PC5-Smessages based on the highest used PPP value used for PC5-Utransmission. For example, the highest used PC5-S transmission may bePPP x. In an example, a range of PPP values for PC5-S messages may bePPP x+y, where y may be a positive or negative integer. For example, ymay be 2, 3, and 4 and so on. The value of y may be preconfigured in aWTRU, signaled by the ProSe function as part of configurationinformation, or provided by an App server over a PC1 interface. Forexample, a highest PPP value used on the PC5-U link may be PPP-3. Thevalue of y may be 3. The PPP value for various PC5-S messages may beselected from a range of PPP 3 to PPP 6, for example, based onpreviously described algorithms or procedures. In an example of usingthe range, a direct communication request message may be sent with PPP 3whereas a link maintenance message may be sent with PPP 6. The range ofPPP for PC5-S messages may change, for example, when the highest usedPPP for PC5-U transmission changes. The range of PC5-S messages maychange from PPP3-PPP6 to PPP2-PPP5, for example, when a packet istransmitted with PPP 2 value.

The WTRU may be configured to use one value or a range of values for xand/or y, for example based on a received configuration. The WTRU mayreceive the configuration from the ProSe function or via other methodssuch as an OMA configuration, a USIM configuration, etc. A WTRU mayforward the configuration to another WTRU for use when transmitting aPC5-S message. For example, a remote WTRU may send a new PC5-S messageto a relay WTRU in order to inform the relay the value (fixed or arange) to use for PC5-S messages.

Systems, methods, and instrumentalities may be provided to determine apriority for PC5-S retransmissions. A ProSe layer may be configured toretransmit PC5-S messages, for example, when it does not receive aresponse from the intended recipient. A ProSe layer in the transmittingWTRU may send a message X times, e.g., for every signaling messagebefore it may determine that the destination WTRU is unavailable.

A ProSe layer may modify (e.g., increase) a priority or the PPP value ofthe message being retransmitted, for example, when a PC5-S message isretransmitted. A ProSe layer may determine how to modify the priorityvalue of the retransmitted message, such as whether a priority isincreased for every retransmission or every second retransmission, etc.A ProSe layer may reset a priority to a previous or original value, forexample, when the ProSe layer receives a response from a recipient WTRU.The subsequent PC5-S messages sent by the ProSe layer to the samedestination may be sent with an earlier or original PPP or priorityvalue.

A logical channel may be created at the AS for a retransmission messagewith a higher priority or new PPP level, for example, when it does notalready exist. The context in the ProSe layer may be updated. Asignaling logical channel may be used, for example, to send the messagewith a new priority level. The AS layer may use an existing logicalchannel with the same priority for data packets to send the PC5-Smessage with the new priority level.

Systems, methods and instrumentalities may be provided to obtain IPaddress information or other relay WTRU identification. A WTRU (or aProSe layer in the WTRU) may send a PC5-S message to request an IPaddress or the prefix of the relay WTRU, e.g., as assigned by the relayWTRU's PDN Gateway (PGW). The PC5-S message may be a new PC5-S message.A request may be made from the application layer, for example, when theWTRU detects that it has lost network coverage and/or has discovered aWTRU-to-Network relay. A WTRU may start a timer to guard a period inwhich a response is expected, e.g., while a re-transmission may be made.A message provided by a WTRU may comprise an identity, e.g., so that arequest may be authorized by its peer WTRU. A WTRU may receive a message(e.g., a response) with information about an IP address used by anotherWTRU. A ProSe layer in the WTRU may forward information (e.g., about theIP address) to the application client. An application client may sendinformation to an application server. A ProSe layer in the WTRU may beconfigured, for example, to send received information to another entityin the network, such as a ProSe function or an application server.

A WTRU (e.g., a relay WTRU) may receive a request to provide its IPaddress or prefix, e.g., as assigned by the PGW. A WTRU may verifywhether a requesting WTRU is authorized to make a request or receiverequested information, for example, by contacting the ProSe function orthe MME and providing an identity of the source WTRU. A relay WTRU maysend a new message to the ProSe Function or a new NAS message to the MMEand may verify a response from these nodes. A WTRU may respond, e.g., toan authorized requesting WTRU, with a new PC5-S message that maycomprise its IP address or prefix assigned by the network.

Systems, methods, and instrumentalities may be provided for priorityhandling of ProSe communications. A WTRU may create a Proximity Services(ProSe) context and may send a new PC5-S message to its peer WTRU (e.g.,relay WTRU), for example, to indicate the priority of an associatedlogical channel ID. A WTRU may create a ProSe context and may send a newPC5-S message to its peer WTRU (e.g., relay WTRU), for example, for oneor more new priority (ies) with which a transmission (Tx) may be made. AWTRU may receive a PC5-S message with a priority level for a ProSecommunication. A WTRU may determine a priority to use and may map thepriority to a corresponding EPS bearer, which may modified or created.The WTRU may respond and may indicate a priority level that can besupported. A remote WTRU may obtain from an Access Stratum (AS) apriority level for downlink (DL) forwarding (e.g., for MultimediaBroadcast Multicast Services (MBMS) data) at a relay WTRU. A remote WTRUmay send a PC5-S message (e.g., a new PC5-S message) to a relay WTRU.The remote WTRU via the PC5-S message may indicate the priority level tobe used on the PC5 link. A relay WTRU may forward MBMS traffic to one ormore remote WTRUs. A relay WTRU may read a priority level of temporarymobile group identity (TMGI) data from System Information Blocks (SIBs).A relay WTRU may set a PC5 logical channel priority, for example,according to TMGI data read from SIBs. A relay WTRU may send a new PC5-Smessage to a remote WTRU, for example, to request a priority level of aTMGI. A relay WTRU may use a received PC5-S message from a remote WTRU,for example, to determine a priority level to be used on a PC5 link onwhich MBMS data is forwarded. A WTRU may determine a priority level fora PC5-S message, for example, based on pre-configurations per messagetype, application ID and/or or a default value. A WTRU may transmit aPC5-S message with a determined priority level. A PC5-S procedure may beused, for example, by a first WTRU to request from a second WTRU an IPaddress and/or prefix that may be used by a target WTRU for EvolvedPacket System (EPS) bearers and/or Packet Data Network (PDN)connections. An IP address and/or prefix may be forwarded by the firstWTRU to the AS, for example, to help with session continuity. Thehighest used point to point protocol (PPP) value for user planetransmission (e.g. PC5-U transmission) may be used as the PPP value foreach of the PC5-S messages.

The processes and instrumentalities described herein may apply in anycombination, may apply to other wireless technologies, and for otherservices. A WTRU may refer to an identity of the physical device, or tothe user's identity such as subscription related identities, e.g.,MSISDN, SIP URI, IP address, etc. WTRU may refer to application-basedidentities, e.g., user names that may be used per application.

The processes described above may be implemented in a computer program,software, and/or firmware incorporated in a computer-readable medium forexecution by a computer and/or processor. Examples of computer-readablemedia include, but are not limited to, electronic signals (transmittedover wired and/or wireless connections) and/or computer-readable storagemedia. Examples of computer-readable storage media include, but are notlimited to, a read only memory (ROM), a random access memory (RAM), aregister, cache memory, semiconductor memory devices, magnetic mediasuch as, but not limited to, internal hard disks and removable disks,magneto-optical media, and/or optical media such as CD-ROM disks, and/ordigital versatile disks (DVDs). A processor in association with softwaremay be used to implement a radio frequency transceiver for use in aWTRU, terminal, base station, RNC, and/or any host computer.

1-40. (canceled)
 41. A first wireless transmit/receive unit (WTRU)comprising: a processor configured to: determine a first PC5 prioritylevel associated with a ProSe session to be established between thefirst WTRU and a second WTRU, wherein the first PC5 priority level isdetermined based on at least an application ID associated with anapplication running on the first WTRU, send a first message to thesecond WTRU, wherein the first message comprises at least an indicationof the application ID and an indication of the first PC5 priority levelfor the ProSe session, and receive a second message from the secondWTRU, wherein the second message comprises an indication of a second PC5priority level associated with the ProSe session.
 42. The first WTRU ofclaim 41, wherein the processor is further configured to determinewhether an existing ProSe session can be used for sending dataassociated with the application.
 43. The first WTRU of claim 41, whereinthe first PC5 priority level is derived based on an association betweenthe application ID and the first PC5 priority level.
 44. The first WTRUof claim 43, wherein the association is preconfigured.
 45. The firstWTRU of claim 41, wherein the processor is further configured to senddata to the second WTRU based on the second PC5 priority level.
 46. Thefirst WTRU of claim 41, wherein the second PC5 priority level is a samePC5 priority level as the first PC5 priority level.
 47. The first WTRUof claim 41, wherein the second PC5 priority level is a different PC5priority level than the first PC5 priority level.
 48. The first WTRU ofclaim 41, wherein the indication of the first PC5 priority level or theindication of the second PC5 priority level is signaled via a PC5signaling, PC5-S, message.
 49. The first WTRU of claim 41, wherein thefirst PC5 priority level for the ProSe session is determined based on arequest from the application.
 50. The first WTRU of claim 41, whereinthe second message is a response message and wherein the second PC5priority level is indicated as accepted by the second WTRU.
 51. A methodimplemented by a first wireless transmit/receive unit (WTRU), the methodcomprising: determining a first PC5 priority level associated with aProSe session to be established between the method and a second WTRU,wherein the first PC5 priority level is determined based on at least anapplication ID associated with an application running on the method;sending a first message to the second WTRU, wherein the first messagecomprises at least an indication of the application ID and an indicationof the first PC5 priority level for the ProSe session; receiving asecond message from the second WTRU, wherein the second messagecomprises an indication of a second PC5 priority level associated withthe ProSe session.
 52. The method of claim 51, further comprisingdetermining whether an existing ProSe session can be used for sendingdata associated with the application.
 53. The method of claim 51,wherein the first PC5 priority level is determined based on anassociation between the application ID and the first PC5 priority level.54. The method of claim 53, wherein the association is preconfigured.55. The method of claim 51, further comprising sending data to thesecond WTRU based on the second PC5 priority level.
 56. The method ofclaim 51, wherein the second PC5 priority level is a same PC5 prioritylevel as the first PC5 priority level.
 57. The method of claim 51,wherein the second PC5 priority level is a different PC5 priority levelthan the first PC5 priority level.
 58. The method of claim 51, whereinthe indication of the first PC5 priority level or the indication of thesecond PC5 priority level is signaled via a PC5 signaling, PC5-S,message.
 59. The method of claim 51, wherein the first PC5 prioritylevel for the ProSe session is determined based on a request from theapplication.
 60. The method of claim 51, wherein the second message is aresponse message and wherein the second PC5 priority level is indicatedas accepted by the second WTRU.